Conversion of (CH.sub.3).sub.3 Al and NH.sub.3 to aluminum nitride is known: Banr, FIAT, Rev. Ger. Sci., Inorg. Chem. II, 155 to 179 (1948). The reaction is as follows: EQU (CH.sub.3).sub.3 Al.NH.sub.3 .fwdarw.(CH.sub.3).sub.2 AlNH.sub.2 .fwdarw.CH.sub.3 AlNH.fwdarw.AlN.
There is no suggestion that the CH.sub.3 AlNH intermediate was isolated or that the final reaction step was conducted in the presence of ammonia.
Laubengayer et al., J. Amer. Chem. Soc., 83, pages 542 to 546 (1961), disclose the reactions of amines at low temperatures with aluminum alkyls or alkyl aluminum chlorides to form 1:1 addition compounds. When such addition compounds having N-H and Al-R bonding are pyrolyzed, amide aluminum polymers, imide aluminum polymers and aluminum nitride are produced.
Laubengayer et al., Inorg. Chem., 1, pages 632 to 637 (1962), disclose the reaction of triphenylaluminum and methylamine in toluene solution to form methylamine triphenylaluminum, then methylaminodiphenylaluminum, and then methyliminophenylaluminum. Triphenylaluminum and dimethylamine form dimethylamine triphenylaluminum which is heated to form dimethylaminodiphenylaluminum.
Cohen et al., J. Chem. Soc., pages 1092 to 1096 (1965), disclose that ethylaluminum dichloride and diethylaluminum chloride form complexes with ammonia. There is no ammonolysis of aluminum-chloride bonds. On heating, the complexes form aluminum-nitrogen polymers. They also disclose the reaction of (C.sub.2 H.sub.5).sub.3 Al and NH.sub.3, and conversion of the product to C.sub.2 H.sub.5 AlNH which is substantially insoluble.
Interrante, in a meeting of the Materials Research Society, April, 1986, at Palo Alto, Calif., disclosed the conversion of C.sub.2 H.sub.5 AlNH to aluminum nitride in the presence of ammonia. The aluminum nitride produced with ammonia contained less carbon than that formed without it. Interrante also disclosed that C.sub.2 H.sub.5 AlNH is converted to aluminum nitride at 300.degree. C. to 900.degree. C. with retention of morphology.
Japanese Patent 54-13439 discloses a method for the production of aluminum nitride in the form of a powder. The method comprises purifying an organoaluminum compound followed by reacting it with ammonia or primary or secondary amines to prepare an aluminum nitride precursor having at least one aluminum nitrogen bond. The aluminum nitride precursor is converted to aluminum nitride by heating it above 400.degree. C. in the presence of an inert gas, vacuum or ammonia gas.
Additional relevant background includes the following: Strength of Aluminum Nitride Whiskers, Gribkov et al., Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy, Vol. 13 (10) pages 1775 to 1778, (1977); Role of Liquid Drops in the Growth of Filamentary Crystals of Aluminum Nitride, Portnoi et al., Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy, Vol. 6 (10) pages 1762 to 1767 (1970); Growth of AlN Whiskers During the Nitriding of Aluminum, Portnoi et al., Poroshkovaya Metallurgiya No. 5 (89) pages 10 to 14 (1970).
Canada 839,321 discloses AlN by carbothermal reduction. Fibers made according to the method disclosed in this patent contain excessive amounts of carbon. Japan 61-124626 discloses a method for making AlN fibers from aluminum metal fibers or from solution of an aluminum compound. U.S. Pat. No. 3,846,527 and U.S. Pat. No. 4,010,233 make reference to metal nitride fibers. This route to AlN fibers uses the carbothermal reductive nitridation reaction with attendant problems of either excess O or C. U.S. Pat. No. 3,529,044 discloses aluminum carbide and that if nitrogen is used, then metal nitride fibers result. The problem with such fibers would be the presence of too much C or O. U.S. Pat. No. 3,658,979 discloses large diameter fibers with a thin film of AlN on the surface. EPA 213,629 discloses aluminum nitride fibers prepared by heating precursor fibers, spun from a solution of aluminum oxychloride and polyvinyl alcohol, in nitrogen. U.S. Pat. No. 4,740,574 discloses AlN structures made by pyrolyzing the condensation product of an organoaluminum compound and an aromatic amine.